Almost four years after her husband's death from Parkinson's disease, former Sacramento County, Calif., supervisor Sandra Smoley has reinvented her life.

She rented out the Fair Oaks home where she lived with her late husband, architect Walter Rohrer, and she moved to a cozy midtown house in the thick of things. In July, she even served as a judge for the Bastille Day waiters races in midtown.

Having emerged from the long shadow of her husband's 12-year illness and death, she says she loves her life now.

"I think some of that has to do with my outgoing, social personality," said Smoley, 76. "I don't want other women to feel that if they're not happy in widowhood, there's something wrong with them. Everybody is their own person in how they handle widowhood."

And grief has its own timetable.

For the almost 11 million Americans age 65 and older who have lost their spouses, the emotional landscape of older age is defined at least in part by grief. In 2009, some 290,000 men in that age group and 648,000 women became widowed, U.S. Census data show.

Every year, at least 1 million people live through the death of a spouse, the Social Security Administration estimates.

But all widowhood experiences are not the same: Some people seem to remain caught in an ongoing loop of mourning for years, while others manage to find new hope and energy in a relatively short time.

Why? Answers have been hard to come by in the past, but research into bereavement is starting to gain new momentum, just as the enormous wave of the baby boomer generation edges into the territory of widowhood.

As it turns out, the late psychiatrist Elisabeth Kubler-Ross' widely known five stages of grief — denial, anger, bargaining, depression and acceptance, which together have become a cultural road map for moving through grief — arose from her observational research on what the dying experience, not the experience of those left behind.

What we think we know about grieving, in other words, is flawed, despite the fact that for most people, widowhood is the most significant turning point of older adulthood.

"Many of these people have been married 50 or 60 years," said Linda Tucker, a clinical psychologist, who directs the Widowed Persons Association of California's grief recovery workshops.

"God love them, your heart wants to break for them sometimes. They've been together all their lives, and suddenly that person's gone."

She knows. Her husband, Dr. William Tucker, died of an aneurysm in his 60s in 1989. Six months later, her daughter was diagnosed with a brain tumor, and not long after her sister died.

"It all came crashing down," she said. "That first year was a terrible time. I didn't think I'd survive it."

But she did, in part because she found new purpose from her grief: She returned to school for her doctorate in psychology, specializing in working with the bereaved.

Despite the pain of losing a spouse, most people move forward. More than 60 percent of widows and widowers handle bereavement with resilience, finding moments of solace, even laughter, alongside their sadness, said Columbia University clinical psychology professor George Bonanno, who researches the science of bereavement.

"We found that most people, when a spouse dies, are deeply pained and sad but essentially fine," said Bonanno. "And older people cope better than younger people. They're more likely to be resilient. We used to think it was the opposite, that an older person would die of a broken heart. That's not true."

According to Bonanno's research, about 30 percent of the bereaved suffer intense, deep grief for a year or more before beginning to recover.

Only about 10 percent of the grieving seem to get stuck in their grief, he has found, drowning in daily yearning for a spouse who has been deceased for years.

While the resilient are at peace with the idea of death long before a loved one dies, his research shows, the opposite is true of people who remain mired in grief: Death alarms them so deeply that they don't want to acknowledge it. They also score highest in terms of being overly dependent on their spouses.

"There's a sense that they depended on the person who died for too many things, and the widow or widower can't be the same person without them there," Bonanno said.

So deep is this prolonged grieving, variously called complicated bereavement, unresolved grief and delayed grief reaction, that an American Psychiatric Association panel this year floated the idea of including extended grief in the definition of major depression in its revised diagnostic manual, the DSM-V, to be published next spring. The panel has since reconsidered.

For Barbara Stewart, the beginning was horrendous. She was stunned when her husband of 31 years, Mark, died unexpectedly from a heart attack in their home in 2001.

"I didn't have his memorial service until a month after he died," said Stewart, 71, a longtime volunteer with the Widowed Persons Association. "The loss of my husband was so traumatic for me. I'd just sit and cry. I couldn't deal with it. I didn't want to.

"Every day, I'd go to the funeral home to make the arrangements, and every day, I'd have to leave."

Even so, she gradually emerged into a new life.

"I believe in today," she said.

The grieving typically experience overwhelming sadness, sleeplessness, loss of appetite, anger, guilt, loneliness and helplessness. They can feel hollow inside. They can be overly sensitive to noise, preoccupied, unable to concentrate.

With complicated grieving, those symptoms become so intrusive over a long period of time that people can hardly function.

"They think about the deceased spouse constantly," said psychologist Dr. Florina Yuger, Sutter Center for Psychiatry's training director. "They can't be present in their life. They can't stand to be by themselves. There's an extreme denial of death and a desperate loneliness, and they often want to die themselves."

Researchers know that the circumstances of death can add a difficult element to bereavement. Survivors of someone who fades slowly from life, from Parkinson's or Alzheimer's, for example, have time to mourn the loss of their loved one for months or years before the actual death. The suddenness of traumatic death, on the other hand, can bring greater emotional suffering to survivors.

And a survivor's own emotional history, including past bouts with depression and post-traumatic stress disorder, can cause normal grief to lapse into a long bout of complicated grief, Yuger said.

"These things from the past get triggered," she said. "This can go on for years. The brain replays the death over and over again. It's hard for the brain to process the information and move forward."

Behavior therapy can help people suffering from complicated bereavement, she said; so can antidepressants.